Measurement, Calendars, and Ephemerides
Selected Reference Guide
Time has been measured
in many ways throughout history and today we live in a world society
with people who use one of a number of systems for telling the
date, days of the week, and what year it is.
Here are selected links
to resources relating to time and time measurement,
calendars, calendar systems, and holidays,
date calculators, and other time keeping resources. There are also links to astronomical
ephemerides, Sun and Moon position/phase calculators. Almanacs are
also included. Quick calendar.
Time is perception and
an abstract method for describing a contiuum of universal activity.
Take a look at some Interesting Time Related Topics.
- The Official U.S.
Time. Exact time measurement from the National Institute of Standards and Technology (NIST). Choose your time zone on the map (US contiguous, Alaska, Hawaii, and Pacific dependents). Also see detailed exhibits on time and calendars.
Master Clock Time. Current
Time from the U.S. Naval Observatory Master
Clock. Set your clock by
one of the most accurate timepieces available.
and Frequency Division in Boulder, Colorado.
An operating unit of the Physics Laboratory of
the National Institute of Standards and Technology
(NIST). Another source for accurate time. Also
has reference sources, glossary, articles on
the history of time calculation, and an exhibit
Clock. Times for given cities.
- WORLDTIME® Interactive world atlas and information on local time as well as sunrise and sunset times in several hundred cities worldwide.
- World Time Zones.
Great visual map, and system for checking time
around the world. Also brief article on Internet
for the entire year. View entire
year or month. Also shows holidays (all or selection).
Calendar and Clock Page. Scroll down for data
and links for time and calendar information, calendars
in different countries and groups, plus astronomical
time and calendar pages, and more.
Date. Enter a date and receive calculations of the date
in 14 different systems (religious, ethnic, government, etc.).
- Blank Calendars. Covers any month since it lists only month and day on it. Useful for planning, etc.
Zone has links to many different calendars;
also by topic.
Creator. Produce a calendar
for any year, with choice of language and other
Years Calendar. Freeware allows
you to view Julian, Gregorian, Hebrew, and
Islamic calendars (link goes to Google search. You can choose which site to download from).
- Perpetual Calendar. Choose a month, and any year from 1583 (the first year of the Gregorian calendar) to the present. View that month, or view an entire year of your choice. Also has links to alternate calendars (Hindu, Islamic, Chinese).
Sun, Moon, Astronomical Calculators
Naval Observatory Astronomical Applications Department.
Contains tables, lists, ephemerides, and calculators
for terrestrial and cosmic activities, including:
Sunrise, Sunset, Moonrise, Moonset, and Twilight
tables, Date conversion tables (e.g., from Julian
to Gregorian), and an FAQ section, which includes
such topics as: Phenomena of the Sun and Moon,
Time measurement and conversion (e.g., Daylight
Savings, Greenwich Mean, etc.), Calendars and Historical
Event data, and links to data sources for: Sunspots
and Solar Activity, Weather and Climate, and Tides.
This site also has pages providing data for: Leap
Years, U.S. Holidays, the 21st Century and the
Sunset & Twilight Times Calculator
Phase Calculator showing a photograph of
the Moon's phase for any date that is entered.
Also available is the:
Reality Moon Phase Pictures calculator from
the U.S. Naval Observatory.
Calendar. Enter your location, dates, and
get a data sheet for your area.
Star Charts. A monthly star chart for 45
degrees north, and one for Southern Hemisphere
skies. Also a separate Planet
Chart and finding guide page is available.
Almanac. Broken down by type of disaster. Choose a date
on the calendar and get a list of events. You can also have
the calendar highlight dates, on which a specific type of